Background Accurate assessment of self-perceived stress is crucial because perceived stress has been linked to post-stroke depression in persons with aphasia and may be related to linguistic performance. Measuring self-reported perceived stress can be difficult in persons with aphasia (PWA) due to linguistic impairments; therefore, using proxy ratings could be an alternative. The accuracy of proxy ratings of perceived stress may be influenced by the proxy’s familiarity with the person with aphasia and/or the condition of aphasia. Additionally, accuracy may be affected by genuine or mistaken signs of perceived stress in PWA due to linguistic behavioural markers common in both stress and aphasia. An observation of stress in a PWA may also trigger a stress response in the proxy. This physiological stress response, known as stress contagion, may be mediated by trait empathy and impact proxy ratings of perceived stress in PWA.Aims The current study investigates the accuracy of proxy ratings of perceived stress made by proxy reporters unfamiliar with PWA and unfamiliar with aphasia by exploring the agreement between PWA self- and unfamiliar proxy-reported stress ratings, the effect of aphasia severity on proxy ratings, stress contagion, and the contribution of trait empathy to proxy ratings.Methods & Procedures Fifty-five proxy reporters unfamiliar with aphasia self-reported their trait empathy and perceived stress, then watched two video cases of unfamiliar PWA and rated the stress of the PWA and their own stress level.Outcomes & Results No correlation was found between self-report and unfamiliar proxy report of PWA perceived stress. Aphasia severity did not affect proxy ratings. The proxy reporter’s self-reported stress matched the PWA’s stress level. Trait empathy did not predict proxy ratings.Conclusions The lack of association between PWA self-report and the ratings of proxy reporters unfamiliar with PWA and aphasia indicates that unfamiliar proxy ratings are not ideal for representing objective measures of perceived stress. While aphasia severity does not affect ratings by proxy reporters unfamiliar with PWA and aphasia, unfamiliar proxy reporters may overestimate perceived stress levels in PWA. The correlation between proxy reporter self-report and PWA self-report suggests that some aspect of stress contagion is present.